import 'dart:async';

import 'package:flutter/material.dart';
import 'package:moonwell_launcher/app/design_system/mw_authentication.dart';
import 'package:moonwell_launcher/app/design_system/mw_shells.dart';
import 'package:moonwell_launcher/app/home_screen/home_screen.dart';
import 'package:moonwell_launcher/features/launcher/data/launcher_api_client.dart';
import 'package:moonwell_launcher/features/preferences/domain/repositories/preferences_repository.dart';
import 'package:moonwell_launcher/service_container.dart';
import 'package:window_manager/window_manager.dart';

class LoginScreen extends StatefulWidget {
  const LoginScreen({super.key});

  @override
  State<LoginScreen> createState() => _LoginScreenState();
}

class _LoginScreenState extends State<LoginScreen> {
  final _usernameController = TextEditingController();
  final _emailController = TextEditingController();
  final _passwordController = TextEditingController();
  final _passwordConfirmationController = TextEditingController();
  final _inviteCodeController = TextEditingController();
  MwAuthenticationMode _mode = MwAuthenticationMode.login;
  bool _termsAccepted = false;
  bool _isLoading = false;
  String? _error;
  String? _success;

  @override
  void dispose() {
    _usernameController.dispose();
    _emailController.dispose();
    _passwordController.dispose();
    _passwordConfirmationController.dispose();
    _inviteCodeController.dispose();
    super.dispose();
  }

  Future<void> _submit() {
    return _mode == MwAuthenticationMode.login ? _login() : _register();
  }

  Future<void> _login() async {
    final username = _usernameController.text.trim();
    final password = _passwordController.text.trim();

    if (username.isEmpty || password.isEmpty) {
      setState(() => _error = 'Введите логин и пароль.');
      return;
    }

    setState(() {
      _isLoading = true;
      _error = null;
      _success = null;
    });

    try {
      final api = getIt<LauncherApiClient>();
      final preferencesRepository = getIt<PreferencesRepository>();
      final session = await api.login(username: username, password: password);
      final manifest = await api.fetchManifest(session.accessToken);
      await preferencesRepository.setLauncherSession(session);

      if (!mounted) return;

      await Navigator.of(context).pushReplacement(
        PageRouteBuilder(
          pageBuilder: (_, _, _) =>
              HomeScreen(session: session, manifest: manifest),
          transitionsBuilder: (_, animation, _, child) {
            return FadeTransition(opacity: animation, child: child);
          },
          transitionDuration: const Duration(milliseconds: 400),
        ),
      );
    } catch (e) {
      if (!mounted) return;
      setState(() {
        _isLoading = false;
        _error = _formatError(e);
      });
    }
  }

  Future<void> _register() async {
    final username = _usernameController.text.trim();
    final email = _emailController.text.trim();
    final password = _passwordController.text;
    final passwordConfirmation = _passwordConfirmationController.text;

    final validationError = _validateRegistration(
      username: username,
      email: email,
      password: password,
      passwordConfirmation: passwordConfirmation,
    );
    if (validationError != null) {
      setState(() => _error = validationError);
      return;
    }

    setState(() {
      _isLoading = true;
      _error = null;
      _success = null;
    });

    try {
      final message = await getIt<LauncherApiClient>().register(
        username: username,
        email: email,
        password: password,
        passwordConfirmation: passwordConfirmation,
        terms: _termsAccepted,
        inviteCode: _inviteCodeController.text,
      );

      if (!mounted) return;
      setState(() {
        _mode = MwAuthenticationMode.login;
        _isLoading = false;
        _termsAccepted = false;
        _passwordConfirmationController.clear();
        _inviteCodeController.clear();
        _success = message;
      });
    } catch (error) {
      if (!mounted) return;
      setState(() {
        _isLoading = false;
        _error = _formatError(error);
      });
    }
  }

  String? _validateRegistration({
    required String username,
    required String email,
    required String password,
    required String passwordConfirmation,
  }) {
    if (!RegExp(r'^[A-Za-z0-9]{3,32}$').hasMatch(username)) {
      return 'Логин должен содержать от 3 до 32 латинских букв или цифр.';
    }
    if (!RegExp(r'^[^@\s]+@[^@\s]+\.[^@\s]+$').hasMatch(email)) {
      return 'Введите корректный email.';
    }
    if (password.length < 8 || password.length > 32) {
      return 'Пароль должен содержать от 8 до 32 символов.';
    }
    if (password != passwordConfirmation) {
      return 'Пароли не совпадают.';
    }
    if (!_termsAccepted) {
      return 'Примите правила сервера и пользовательское соглашение.';
    }
    return null;
  }

  void _setMode(MwAuthenticationMode mode) {
    setState(() {
      _mode = mode;
      _error = null;
      _success = null;
    });
  }

  String _formatError(Object error) {
    final raw = error.toString();
    if (raw.startsWith('Exception: ')) return raw.substring(11);
    return raw;
  }

  @override
  Widget build(BuildContext context) {
    return MwLoginShell(
      form: MwAuthenticationForm(
        usernameController: _usernameController,
        emailController: _emailController,
        passwordController: _passwordController,
        passwordConfirmationController: _passwordConfirmationController,
        inviteCodeController: _inviteCodeController,
        mode: _mode,
        onModeChanged: _setMode,
        termsAccepted: _termsAccepted,
        onTermsChanged: (value) => setState(() => _termsAccepted = value),
        loading: _isLoading,
        error: _error,
        success: _success,
        onSubmit: _submit,
      ),
      onDrag: windowManager.startDragging,
      onDoubleTap: () => unawaited(_toggleMaximized()),
      onMinimize: windowManager.minimize,
      onMaximizeRestore: () => unawaited(_toggleMaximized()),
      onClose: () => unawaited(windowManager.destroy()),
    );
  }

  Future<void> _toggleMaximized() async {
    if (await windowManager.isMaximized()) {
      await windowManager.unmaximize();
    } else {
      await windowManager.maximize();
    }
  }
}